The invention relates to a method of manufacturing, in four masking steps, an active matrix for a liquid crystal display screen whose control transistors are of the top-gate type. The liquid crystal display screen obtained by means of this method is particularly suitable for use in image projection systems.
Direct-vision or projection liquid crystal display screens are generally composed of rows (selection rows) and columns (data rows), with the pixel electrodes connected to these rows via transistors situated at their intersections. The gates of these transistors constitute the selection rows and are controlled by peripheral control circuits which scan the rows and turn on the transistors of each row in that the electrodes are biased by means of the data rows connected to the other peripheral control circuits, and the optical properties of the liquid crystal between these electrodes and the counter electrode (or the reference electrode) are modified so that images are formed on the screen.